This invention relates generally to belt conveyors. More specifically, it relates to tandem drive assemblies for belt conveyors and particularly to those used in underground coal mines.
It is well known to those familiar with the use of belt conveyors in underground coal mines that coal dust and fines accumulate on the ground beneath the drive assemblies. Most of this collects in the area just beneath the drive pulleys. Coal dust is hazardous because it burns easily, and is violently explosive when agitated and suspended into the air. It is especially hazardous if allowed to accumulate under a belt conveyor drive assembly because several malfunctions possible with this equipment can create enough heat to ignite or explode the coal dust. The powerful electric drive motors can overheat under heavy, sustained loads. The belt can mis-align, rub against the drive frame and generate heat by friction. A troughing or return pulley can freeze up; and the resulting friction can quickly generate heat and sparks. Ventilating fans on the drive motors can suspend coal dust in air and bring it into contact with overheated parts.
Because of these dangers, coal dust accumulating around and under a conveyor drive should be cleaned out regularly. Unfortunately, head room restrictions require that belt conveyor drives be built low to the ground. As a result all conventional drives have side members or beams directly on the ground in the area flanking the tandem drive pulleys where most of the dust collects. It is not possible to remove this dust by inserting a scoop or shovel through the sides of the machine because there are no ground level openings large enough. Because of this, the conveyor must be stopped and someone has to reach in from the outbye end of the drive unit and drag the dust out lengthwise of the conveyor. This is awkward, slow and dirty work, and takes the conveyor out of production for an objectionably long time. This situation accordingly is in need of improvement.